Population density increases
<u>Answer:</u> The mass of sodium chloride solution present is 0.256 grams.
<u>Explanation:</u>
We are given:
39.0 % of sodium in sodium chloride solution
This means that 39.0 grams of sodium is present in 100 grams of sodium chloride solution
Mass of sodium given = 100 mg = 0.1 g (Conversion factor: 1 g = 1000 mg)
Applying unitary method:
If 39 grams of sodium metal is present in 100 grams of sodium chloride solution
So, if 0.1 grams of sodium metal will be present in = 
of sodium chloride solution.
Hence, the mass of sodium chloride solution present is 0.256 grams.
Pure water may be identified by its density: it will have the lowwest density of the three solutions, given that the solutes (salt and sugar) increase the density (this is the easiests and quickest way).
You can also measure the freezing points or boling points to identify the pure water because the solutes depress the freezing points and increase the boling points.
To differentiate sugar water and salt water, you can probe which one conducts electricity, because salt water is a conductor (given that it ionizes into Na+ and Cl-) but sugar water is not a conductor.
STP is abbreviation for Standard Temperature and Pressure at which the temperature is 273 K and pressure is 1 atm
- At these conditions the molar volume is equal to 22.4 L
so 1 mole of SO₂ volume = 22.4 L
? mole of SO₂ volume = 2.5 L
number of moles = 2.5 / 22.4 = 0.1116 mol
mass of SO₂ = 0.1116 * 64.063 = 7.15 g
